The invention is related to superconducting wire having at least one filament of superconducting material. More particularly, the invention relates to a multi-filament superconducting wire comprising a zirconia-stabilized, niobium tin superconductor and a matrix material, and a method of making such a multi-filament superconducting wire.
Superconducting wires comprising multiple filaments of niobium-based superconductors, such as niobium tin (hereinafter referred to as “Nb3Sn”), are used in a variety of electromagnetic applications, such as magnets, motors, and transformers. To maintain sufficient critical current density in the superconducting wire during operation at cryogenic temperatures of less than 17.5 K, the Nb3Sn comprising filaments within the wire must have an ultra-fine grain size of less than about 1 micron. One of the processes that is used to manufacture multi-filament Nb3Sn wire is the “bronze process,” in which ultra-fine grains of Nb3Sn are formed on the surface of wire-drawn niobium filaments by heat treatment for several days at relatively low temperatures.
The length of the heat treatment required to produce ultra-fine grain Nb3Sn is exceedingly time-intensive and uneconomical. Therefore, what is needed is a superconducting wire comprising ultra-fine grain Nb3Sn that is formed by a more rapid process. What is also needed is a method of more rapidly making a multi-filament superconducting wire comprising ultra-fine grained Nb3Sn.